A video from inside the Radisson Blu hotel in Mali's capital has emerged, believed to have been filmed by one of the hostages.

Footage also shows the scene outside the hotel as police gather around the building.

The Brussels-based Rezidor Hotel group that operates the hotel said the assailants had "locked in" 140 guests and 30 employees, though Malian army commander Modibo Nama Traore later said that 80 people had been released.

Any number of Muslim extremist groups could be behind the attack, which unfolded one week after the attacks on Paris that killed 129 people. A handful of jihadi groups seized the northern half of Mali in 2012 but were ousted from cities and towns by a French military intervention.

Traore said 10 gunmen stormed the hotel shouting "Allahu Akbar," or "God is great," in Arabic before firing on the guards. A staffer at the hotel who gave his name as Tamba Diarra said over the phone that the attackers used grenades in the assault.

The US Embassy in Mali asked citizens to shelter in place amid reports of an "ongoing active shooter operation" at the hotel in Bamako. People in the area ran for their lives along a dirt road as a soldier in full combat gear escorted them to safety.

Some guests were able to escape the hotel. Monique Kouame Affoue Ekonde, an Ivorian, said she and six other people, including a Turkish woman, were escorted out by security forces as the gunmen rushed "toward the fifth or sixth floor."